The comma separated values format (CSV) has been used for exchanging and converting data between various spreadsheet programs for quite some time. It can be used as an Import/Export feature on multiple old and modern applications. And we could say is the de facto standard for data exchange between all architectures of computing.
Creating and manipulating CSV files in Delphi is quiete easy using powerfull CSV library from Winsoft
Table of Contents
Installation
Download latest version here, and unzip downloaded file to your default components folder.
This is a non-visual library, so you don’t need to install it on IDE.
Add folder according your Delphi version and Platform in Tools->Options->Language->Delphi->Library to Library Path
Samples
In the following example we will implement a generic import/export functionality to our existing simple application for contacts management.
Creating a new CSV file from Dataset (Export function)
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procedure ExportToFile(ADataset : TDataset; AFileName : string) var CSV: TCSVWriter; i: integer; value: string; begin CSV := TCsvWriter.Create(AFileName) ADataset.First; // first we need to create header for fieldnames for i := 0 to ADAtaSet.FieldList.Count - 1 do begin CSV.Write(ADataset.Fields[i].fieldName); end; // now we will loop over the Dataset to set record values try while not ADataset.eof do begin // Append a new line CSV.NextLine; for i := 0 to ADataSet.FieldList.Count - 1 do begin // special case for date and datetime fields to avoid conflicts with date separators case ADataset.Fields[i].FieldType of ftDate: Value := FormatDateTime('yyyymmdd', ADataset.Fields[i].AsDatetime); ftDateTime: Value := FormatDateTime('yyyymmddhhnnsszzz', ADataset.Fields[i].AsDatetime); ftTime: Value := FormatDateTime('hhnnsszzz', ADataset.Fields[i].AsDatetime); else Value := ADataset.Fields[i].AsDatetime; end; end; ADataset.Next; end; finally CSV.Free; end; end; |
Loading an existing CSV file to Dataset (Import function)
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procedure ImportFromFile(ADataset : TDataset; AFilenanme ; string); var CSV: TCSV; i,j: integer; Value, FieldName: string; slFields: TStringList; fs: TFormatSettings; begin if not FileExists(AFileName) then Exception.Create('File ' + AFileName + ' does not exist'); CSV := TCSV.Create; slFields:=TStringList.Create; fs := TFormatSettings.Create; fs.DateSeparator := ''; fs.ShortDateFormat := 'yyyymmdd'; fs.TimeSeparator := ''; fs.ShortTimeFormat := 'hhmmss'; fs.LongTimeFormat := 'hhmmss'; try CSV.LoadUtf8File(AFileName); // mapping for proper fields names info on first line of file for i := CSV.FieldsCount[0] do begin slFields.Add(CSV.Fields[0, i]) end; for i := 1 to CSV.LineCount - 1 do begin ADataset.Append; for j := 0 to CSV.FieldCount[i] do begin // get field value of current record Value := CSV.Fields[i, j]; FieldName := slFields.Strings[j]; case ADataset.FieldByName(FieldName).FieldType of ftDate , ftDateTime, ftTime: Value := StrToDateTime(Value, fs); end; ADataset.FieldByName(FieldName).Value := Value; end; ADataSet.Post; end; finally CSV.Free; slField.Free; fs.Free; end; end; |
Head over and check out the full WINSOFT CSV in Delphi and C++Builder
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Is the call to StrToDateTime in ImportFromFile meant to be StrToDateTime(Value, fs)?
Wow, this article was written just prior to me starting to edit for the blog. We do try to vet the content a lot more closely nowadays although things do still sneak through. It definitely had a few quality issues, sorry about that!
I’ve fixed the layout to match the preferred Embarcadero coding style, corrected the typos in the code and, yes, thanks to you Jeff I’ve also corrected the
StrToDateTimecall to be the overloaded version which uses the optional format settings argument which was the original point of the article in the first place… doh!Thanks for letting us know. 😃👍